BP Flashcards

1
Q

3 anti fungal drugs and their targets

A

Azoles - block alpha 14 demethylase (a fungal cytochrome P450) = formation of ergosterol = increased cell wall permeability, inhibition of replication
Polyenes - bind to sterols in the membrane, bind to ergosterol with higher affinity - forms ion channel = loss of rigidity
Mitotic inhibitors = inhibit cell division by interfering with spindle formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 main administration methods for anti-fungals

A

Oral
IV
Topical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Calculate clearance

A

Cl = Vd x Ke

Dose/AUC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Ke

A

Elimination constant

0.693/half life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Vd

A

Volume of distribution

Drug in body/drug in plasma conc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is clauvanic acid commonly prescribed with beat lactic antibiotics?

A

Inhibits beta lactamases which break down beta lactic antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Graded Vs Quantal curves

A

Graded looks at the response of an individual with increased concentration
Quantal looks at a specific response of a population with an increased concentration
Graded = sigmoidal
Quantal = n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What 2 drugs increase likelihood of candidiasis infection?

A

Glucocorticosteroids

Immunosuppressants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What type of drug is morphine?

What is it used to treat?

A

Opioid

Moderate to severe pain, terminal care

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of drug is codeine?
What is it used to treat?
Side effects?

A

Weak opioid
Mild to moderate pain, cough suppression, antidiarrhoeal
Constipation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where do benzodiazepine accumulate, why?
Side effects
Mechanism of action

A

Body fat because they have a high lipid solubility
Long lasting hangover, amnesia, sexual fantasies, dependency
Binds to specific regulatory site on the GABAa receptor - increasing the affinity for GABAa molecule = increased frequency of binding = increased inhibition of neuronal signals to brain = treat anxiety

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do benzodiazepines differ from barbiturates?

A

Barbituates increase the binding duration of GABA, benzodiazepines increase the frequency of binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

2 ways of sedating a patient other than benzodiazepine?

A

Inhalation of nitric acid

H1 antagonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does heparin bind to? mechanism of action?

What is a better version of heparin, why?

A

Antithrombin
Binds to antithrombin III which accelerates the inhibition of thrombin and clotting factors
Low molecular weight heparins have more constant activity because they only bind antithrombin III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is heparin administered? why?

A

IV or SC

Not absorbed from the gut (high PPB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Method of warfarin administration?

A

Oral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Mechanism of action of warfarin?

A

Inhibits hepatic synthesis of vit K dependent clothing factors by inhibiting vit K reductase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Speed of action for warfarin?

A

1-2 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does aspirin cause?

A

NSAID = anti platelet, antipyretic, analgesic, anti-inflammtory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does aspirin have an antiplatelet action?

A

Inhibits eiconsaoid production by inhibiting COX
Inhibits COX mediated release of TXA2 and PGI2
TXA2 = promotes aggregation
PGI2 = inhibits aggregation
PGI2 is endothelium derived so makes more
TGA2 is platelet derived so no more made
= reduce platelet aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do antidepressants work?

A

TCA’s inhibit 5-HT and NA reuptake but this isn’t selective to also blocks M1 H1 and alpha 1
SSRI are selective
Monamine oxidase inhibitors = block the breakdown of Na to amines
More NA or 5HT in neurotransmitter in synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do antidepressants cause dry mouth?

A

TCA are not selective block M1 receptors = block parasympathetic effects = decreased saliva flow = dry mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Mechanism of action of LA?

A

Block electrical signalling in neurones by blocking Na+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How to calculate half life?

A

From graph or 0.693/Ke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
2 pregnancy hormones related from anterior pituitary gland and function of each?
``` FSH = development of follicle LH = caused progesterone release from ovaries ```
26
2 pregnancy hormones related from ovary? function?
Progesterone - renders endometrium dutiable fro implantation, inhibits FSH and LH Oestrogen - proliferation of endometrium, inhibits FSH
27
Metabolism of NA
Re-uptake transporter transports it back into pre-synaptic vesicle where it is metabolised to amines by MAO
28
Metabolism of ACh
By acetylcholinesterase in the synapse
29
What effects rate of distribution?
Membrane permeability and blood perfusion
30
What effects extent of distribution?
Lipid solubility, pH-Pka, tissue binding, PPB
31
Competitive orthosteric antagonist?
Binds reversibly to the active site (same site as drug) | Prevents agonist action but can be overcome with increased agonist concentration
32
Concentration response curve of competitive orthosteric antagonist?
Parallel but shifted to the right
33
What does a partial agonist appear like?
Maximum response falls short to the maximal response a system is capable of
34
What is aciclovir best against?
Herpes simplex virus
35
How is aciclovir selective?
Needs to be phosphorylated to be effective, so utilise simplex specific kinase for monophsophorylation
36
Why can metronidazole not be taken with alcohol?
Metronidazole inhibits aldehyde dehydrogenase which is an enzyme needs for ethanol metabolism Nausea, stomach pain, hot flush, palpitations
37
Components on combined pill and functions?
Contains oestrogen and progesterone Oestrogen inhibits FSH release via negative feedback = prevents development of follicle Progesterone inhibits release of LH, makes cervical mucus less suitable for sperm and prevents ovulation
38
What is the phase I reaction? | Aim?
Most commonly an oxidation reaction mediated by cytochrome P450 Addition of functional group to decrease lipid solubility May activate pro-drugs
39
Parasympathetic receptors
1. Ach (neuronal nicotinic) | 2. Ach (Muscarinic)
40
Sympathetic receptors
1. Ach (neuronal nicotinic) | 2. NA (adrenoreceptor)
41
What is the result of blocking K+ channels on the release of insulin?
Glucose into cell Glucose --> ATP ATP opens K+ channels and move out When ATP high, K+ channel blocked = depolarisation = Ca2+ channel opens, Ca2+ and causes insulin release
42
Depolarising block? | What molecules cause this?
Stimulation of muscle type nicotinic receptors by Ach cause depolarisation and contraction of muscle fibre Muscle type nicotinic receptor agonist are not metabolised quickly by acetylcholinesterase = persistent depolarisation = loss of further excitability = depolarising block = paralysis/muscle relaxation
43
What drug stimulates release of insulin?
Potassium channel blocker e.g. sulphonylureas | This will open Ca2+ channels and release insulin by exocytosis
44
What type of reaction changes the ketone group to hydroxyl group on warfarin?
Phase I metabolism by cytochrome P450
45
What mechanism moves drugs from blood to tissue?
Distribution
46
What do polyenes such as nystatin and amphotericin target?
Bind directly to sterols in the membrane (higher affinity for ergosterol) and from ion channels in the membrane
47
What type of data would be used to generate a graded response curve?
% response of a single person at different concentrations of drug
48
What type of data would be used to generate a quantal response curve?
A specified response to a drug within a concentration (e.g. muscle contraction/100000) against different concentrations of a drug
49
What class of drugs are highly protein bound but poorly absorbed?
Benzodiazepines = highly lipophilic
50
Calculate volume of distribution?
Dose administered/concentration in blood
51
If a drug has high Vd where is it likely to be found?
Outside of plasma, bound to tissue
52
If a drug is too large to cross plasma membrane like warfarin, what will its Vd be like?
Low - it is confined to the plasma
53
Which type of drug would have a higher Vd a) Drugs distributed in the extracellular compartments, they cannot enter cells easily (low lipid solubility) b) Drugs distributed in the body water, lipid soluble so can readily cross membranes?
b
54
What hormones does the combined pill have an effect on?
Contains progesterone and oestrogen which provide negative feedback loops to hypothalamus and anterior pituitary to prevent GRH, LH and FSH release
55
What enzyme converted paracetamol in phase I reaction?
CYP450 to a toxic metabolite which is detoxified by glutathione (phase II)
56
In overdose how does paracetamol metabolism differ to therapeutic dose?
Normally metabolised mainly by phase II (glucuronic acid), and a little by phase I to a toxic metabolite which is detoxified by glutathione (phase II) In overdoes the phase II pathways are saturated so more is metabolised by CYP450 to a toxic metabolite Glutathione is depleted so is not detoxified = tissue damage and hepatic necrosis
57
Action of cortisol?
Increase and maintain normal blood glucose levels by increasing gluconeogenesis decreasing glucose uptake into muscles and adipose decrease in protein synthesis so AA are free fro gluconeogenesis
58
Disorder of cortisol? Cause? Treatment?
Cushings syndrome = hypercortisoleamia Adrenal or pituitary tumour or chronic glucocorticoid therapy (bushings-like symptoms not actually cushings syndrome) Removal of tumour or use of drug that inhibits cortisol production
59
Consequences of Cushing's syndorme?
Buffalo hump Hypertenison Thin arms and legs, increased abdominal fat Poor wound healing
60
How does IV looks different to other methods of administration on graph?
Iv will have highest blood concentration straight away, others will start lower and gradually increase as absorption occurs
61
Which combinations of the following drug classes might be used to treat inflammation? 1. Histamine H1 antagonists 2. Histamine H2 antagonists 3. Glucocorticoid antagonists 4. Glucocorticoid agonists 5. Cyclooxygenase inducers 6. Cyclooxygenase inhibitors ``` A) 2, 3 and 4 B) 1 and 2 C) 1, 3 and 5 D) 1, 4 and 6 E) 2 and 6 ```
D Histamine is an inflammatory mediator - needs to be inhibited.Different histamine receptors have different effects, H1 = inflammatory, H2 = acid secretion in the gut = not needed Glucocorticoids are anti-inflammatory so should be stimulated COXII = activated in inflammation = inhibited in anti-inflammation
62
Mrs Beecham was given the antifungal agent, Nystatin for an oral candidiasis infection. 2 days after prescribing the treatment she returns to the clinic with low renal function. What is the likely underlying mechanism for this adverse effect? A) Altered amino acid transport B) Binding to 14-α demethylase C) Hypokalaemia induced by increased cell permeability D) Inhibition of CYP P450 function E) Increased CYP P450 function
Nyastin = polyene = causes ion channels in the membrane due to binding of ergosterol = side effects to do with membrane permeability
63
Describe what is meant by the term distributional selectivity? Why is this concept important in the chemotherapy of infectious diseases?
More of the drug in the infected cell than the host cell (selectively accumulates into the infected cell over the host cell) It only goes to one part of the body (administered into the infected area only) By ensuring a higher concentration is in the infected cell than the host cell means it is non-toxic to the host cell Chemotherapy exploits the difference between invading and host species
64
What type of drug is preferably absorbed from oral (SI) route?
Weak bases
65
Why is SI a good place for absorption?
Large, highly permeable, vascularised SA | Enterocytes contain drug metabolising enzymes
66
Factors effecting rate of GI absorption
Rate of gastric emptying Gut pH = poor absorption of strong acids and bases Particle size Physico-chemical interactions e.g. tetracycline binds to Ca2+ rich food
67
Bioavailability | How is it calculated?
Fraction of administered dose entering systemic circulation Area under the curve of a concentration time curve
68
Where does 1st pass metabolism occur?
Liver and intestine
69
pKa
Strength of acid/base
70
pKa=pH
50% ionised
71
Exposure to what can effect elimination?
Exposure to inducers or inhibitors | Increase or decrease metabolism
72
3 steps of renal excretion?
Glomerular filtration, tubular secretion, tubular reabsorption
73
Glomerular filtration dependent on:
Concentration of free drug in the plasma | Molecular weight
74
2 systems for tubular secretion? Effect of PPB Competetion
Acid and basic No effect from PPB because it is carrier mediated transport Some drugs use same transporter = competition
75
Tubular reabsorption dependent on:
``` Lipid solubility (high = excreted from tubule, low = concentrate in urine) pH of tubule fluid (alkaline = acids ionised so concentrate in urine, bases move out) ```
76
How are NSAIDs anti-inflammatory?
Decreased prostaglandin cause less sensitisation fo nociceptors to effects of mediators
77
Side effects of aspirin? | Why can it not be given to children?
GI irritation, hypersensitivity, vertigo (high dose) In children can cause Reye's syndrome
78
Why is ibuprofen preferred over aspirin?
Uncommon and mild side effects, some sensitivity reactions, less GI irritation. Suitable for children
79
What effects does inflammation have on paracetamol?
Less analgesic effects
80
Action of opioids?
Agonists of Mu opioid receptor which is a Gi coupled receptor
81
Therapeutic effect of opioids
Analgesia, euphoria, sedation
82
Why is administered dose of opioids higher than therapeutic dose?
Extensive first pass metabolism
83
Opioid absorption from the gut?
Erratic
84
Adverse effects of opioids?
``` CNS = respiratory depression, drowsiness, sedation PNS = constipation, histamine release, pinhole pupils ```
85
Classification of ADR's with examples
``` A = Augmented = link to pharmacological action of drug e.g. bradycardia from B blockers, tachycardia from muscarinic antagonists B = Bizarre = don't link to pharmacological action of drug e.g. anaphylaxis from penicillin C = Chronic = as a result of chronic treatment e.g. Cushing's syndrome from glucocorticoid therapy D = Delayed = in patient after treatment or in children of patient after birth e.g drug in pregnant mothers found to increase risk of vaginal cancer in offspring in their 20s E = End of treatment = withdrawal symptoms e.g. adrenal insufficiency after glucocorticoid treatment ```
86
Fastest type of receptor?
Ligand gated
87
Drugs that potentiate function of anti-coagulants?
Anti-platelet drugs e.g. Aspirin Cytochrome P450 inhibitors Inhibitors of Vit K reduction
88
Drugs that decrease function of anti-coagulants?
Cytochrome P450 inducers | Drugs that reduce absorption
89
Action of B1 and B2 agonists?
Increase HR | Bronchodilation